reorganize process related sources into a process/ directory

src/process/handle.rs

@@ -0,0 +1,49 @@
+use std::ops::Deref;
+
+use windows::Win32::Foundation::{CloseHandle, HANDLE, INVALID_HANDLE_VALUE};
+use windows::Win32::System::Threading::{
+    OpenProcess, PROCESS_ALL_ACCESS, PROCESS_VM_READ, PROCESS_VM_WRITE,
+};
+
+#[derive(Debug, Default)]
+pub struct Handle(pub HANDLE);
+
+impl Deref for Handle {
+    type Target = HANDLE;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl Drop for Handle {
+    fn drop(&mut self) {
+        if self.0 != INVALID_HANDLE_VALUE {
+            unsafe {
+                if let Err(why) = CloseHandle(**self) {
+                    eprintln!("couldn't close handle: {why}");
+                };
+            }
+        }
+    }
+}
+
+impl Handle {
+    pub fn from_pid(pid: u32) -> Result<Self, crate::Error> {
+        let handle = unsafe {
+            OpenProcess(PROCESS_ALL_ACCESS, false, pid)
+                .or_else(|_| OpenProcess(PROCESS_VM_READ | PROCESS_VM_WRITE, false, pid))
+                .map_err(|why| {
+                    crate::Error::HandleError(format!(
+                        "couldn't open process with needed access: {why}",
+                    ))
+                })?
+        };
+        if handle == INVALID_HANDLE_VALUE {
+            return Err(crate::Error::HandleError(
+                "couldn't get a valid handle".to_string(),
+            ));
+        }
+        Ok(Self(handle))
+    }
+}